For packaging photosensitive materials, that is a variety of materials whose commercial value is lost on exposure to light, a packaging material which completely shields the light is used. The properties required of the packaging material include non-impaired photographic properties of the photosensitive materials, light-shielding properties, moisture-proofness, physical strength, such as fracture strength, tearing strength, impact breakage strength or Gerbotester strength, heat-sealing properties, such as heat-sealing strength, chronological heat-sealing strength or hot sealing strength, and anti-static properties. The following publications have been issued in this technical field.
A packaging bag employing a laminated film having a metal layer and having a polyolefin (PO)-based resin layer including a PET layer/adhesive layer/aluminum foil/light-shielding material and a non-ionic anti-static agent, as viewed from the outer side, with an optical density of not less than 7.5 (packaging bag for a photosensitive material disclosed in JP Patent Kokoku JP-B-63-26697).
A packaging film having a light-shielding L-LDPE resin film layer containing not less than 50 wt % of an L-LDPE resin and not less than 1 wt % of a light-shielding material(JP-Patent Kokoku JP-B-2-2700 for a film for packaging a photosensitive material). A laminated film formed by laminating an L-LDPE resin film layer substantially containing no light-shielding material and a completely light-shielding flexible sheet (JP Patent Kokoku JP-B2-2701 for a packaging material for a photosensitive material). A packaging material for a photosensitive material formed by laminating, via an adhesive layer, a polypropylene resin film layer on an innermost L-LDPE film layer containing not less than 40 wt % of L-LDPE resin, carbon black and a fatty acid amide-based lubricant (JP Patent Kokoku JP-B-5-40889 for a packaging material for a photosensitive material).